Lens module

ABSTRACT

A lens module includes a first lens having refractive power; a second lens having refractive power, both surfaces thereof being convex; a third lens having refractive power, both surfaces thereof being concave; a fourth lens having refractive power; a fifth lens having refractive power, an object-side surface thereof being convex; and a sixth lens having refractive power and having one or more inflection points on an image-side surface thereof, an object-side surface thereof being convex. The first to sixth lenses are sequentially disposed in numerical order from the first lens to the sixth lens from an object side of the lens module toward an image side of the lens module.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims the benefit under 35 USC 119(a) of Korean PatentApplication No. 10-2014-0161135 filed on Nov. 18, 2014, in the KoreanIntellectual Property Office, the entire disclosure of which isincorporated herein by reference for all purposes.

BACKGROUND

1. Field

This application relates to a lens module having an optical systemincluding six lenses.

2. Description of Related Art

A lens module mounted in a camera module provided in a mobilecommunications terminal includes a plurality of lenses. For example, thelens module may include six lenses in order to configure ahigh-resolution optical system.

However, when a high-resolution optical system is configured using theplurality of lenses as described above, a length (the distance from anobject-side surface of a first lens to an image plane) of the opticalsystem may be increased. In this case, it is difficult to mount the lensmodule in a thin mobile communications terminal.

SUMMARY

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used as an aid in determining the scope of the claimed subjectmatter.

In one general aspect, a lens module includes a first lens havingrefractive power; a second lens having refractive power, both surfacesthereof being convex; a third lens having refractive power, bothsurfaces thereof being concave; a fourth lens having refractive power; afifth lens having refractive power, an object-side surface thereof beingconvex; and a sixth lens having refractive power and having one or moreinflection points on an image-side surface thereof, an object-sidesurface thereof being convex; wherein the first to sixth lenses aresequentially disposed in numerical order from the first lens to thesixth lens from an object side of the lens module toward an image sideof the lens module.

An object-side surface of the first lens may be convex.

An image-side surface of the first lens may be convex.

An object-side surface of the fourth lens may be convex.

An image-side surface of the fourth lens may be concave.

An object-side surface of the fourth lens may be concave.

An image-side surface of the fourth lens may be convex.

An image-side surface of the fifth lens may be concave.

The image-side surface of the sixth lens may be concave.

In the lens module, |r1/T1|<17.0 may be satisfied, where r1 is a radiusof curvature of an object-side surface of the first lens, and T1 is athickness of the first lens on an optical axis.

In the lens module, |f6/f|<79.0 may be satisfied, where f is an overallfocal length of an optical system including the first to sixth lenses,and f6 is a focal length of the sixth lens.

In the lens module, f5/f<−3.0 may be satisfied, where f is an overallfocal length of an optical system including the first to sixth lenses,and f5 is a focal length of the fifth lens.

In the lens module, |(r7+r8)/(r7−r8)|<200 may be satisfied, where r7 isa radius of curvature of an object-side surface of the fourth lens, andr8 is a radius of curvature of an image-side surface of the fourth lens.

In the lens module, wherein |n3−n4|<0.1 may be satisfied, where n3 is arefractive index of the third lens, and n4 is a refractive index of thefourth lens.

In another general aspect, a lens module includes a first lens havingnegative refractive power; a second lens having positive refractivepower; a third lens having negative refractive power; a fourth lenshaving negative refractive power; a fifth lens having negativerefractive power; and a sixth lens having negative refractive power andhaving one or more inflection points on an image-side surface thereof;wherein the first to sixth lenses are sequentially disposed in numericalorder from the first lens to the sixth lens from an object side of thelens module toward an image side of the lens module.

In the lens module of claim 15, 5.0<|(r9+r10)/(r9−r10)|<21.0 may besatisfied, where r9 is a radius of curvature of an object-side surfaceof the fifth lens, and r10 is a radius of curvature of an image-sidesurface of the fifth lens.

Other features and aspects will be apparent from the following detaileddescription, the drawings, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view of a first example of a lens module.

FIG. 2 is a graph including curves representing modulation transferfunction (MTF) characteristics of the lens module illustrated in FIG. 1.

FIG. 3 is a graph including curves representing aberrationcharacteristics of the lens module illustrated in FIG. 1.

FIG. 4 is a table representing characteristics of the lenses of the lensmodule illustrated in FIG. 1.

FIG. 5 is a table representing aspherical surface coefficients of thelenses of the lens module illustrated in FIG. 1.

FIG. 6 is a view of a second example of a lens module.

FIG. 7 is a graph including curves representing MTF characteristics ofthe lens module illustrated in FIG. 6.

FIG. 8 is a graph including curves representing aberrationcharacteristics of the lens module illustrated in FIG. 6.

FIG. 9 is a table representing characteristics of the lenses of the lensmodule illustrated in FIG. 6.

FIG. 10 is a table representing aspherical surface coefficients of thelenses of the lens module illustrated in FIG. 6.

FIG. 11 is a view of a third example of a lens module.

FIG. 12 is a graph including curves representing MTF characteristics ofthe lens module illustrated in FIG. 11.

FIG. 13 is a graph including curves representing aberrationcharacteristics of the lens module illustrated in FIG. 11.

FIG. 14 is a table representing characteristics of the lenses of thelens module illustrated in FIG. 11.

FIG. 15 is a table representing aspherical surface coefficients of thelenses of the lens module illustrated in FIG. 11.

FIG. 16 is a view of a fourth example of a lens module.

FIG. 17 is a graph including curves representing MTF characteristics ofthe lens module illustrated in FIG. 16.

FIG. 18 is a graph including curves representing aberrationcharacteristics of the lens module illustrated in FIG. 16.

FIG. 19 is a table representing characteristics of the lenses of thelens module illustrated in FIG. 16.

FIG. 20 is a table representing aspherical surface coefficients of thelenses of the lens module illustrated in FIG. 16.

FIG. 21 is a view of a fifth example of a lens module.

FIG. 22 is a graph including curves representing MTF characteristics ofthe lens module illustrated in FIG. 21.

FIG. 23 is a graph including curves representing aberrationcharacteristics of the lens module illustrated in FIG. 21.

FIG. 24 is a table representing characteristics of the lenses of thelens module illustrated in FIG. 21.

FIG. 25 is a table illustrating aspherical surface coefficients of thelenses of the lens module illustrated in FIG. 21.

Throughout the drawings and the detailed description, the same referencenumerals refer to the same elements. The drawings may not be to scale,and the relative size, proportions, and depiction of elements in thedrawings may be exaggerated for clarity, illustration, and convenience.

DETAILED DESCRIPTION

The following detailed description is provided to assist the reader ingaining a comprehensive understanding of the methods, apparatuses,and/or systems described herein. However, various changes,modifications, and equivalents of the methods, apparatuses, and/orsystems described herein will be apparent to one of ordinary skill inthe art. The sequences of operations described herein are merelyexamples, and are not limited to those set forth herein, but may bechanged as will be apparent to one of ordinary skill in the art, withthe exception of operations necessarily occurring in a certain order.Also, descriptions of functions and constructions that are well known toone of ordinary skill in the art may be omitted for increased clarityand conciseness.

The features described herein may embodied in different forms, and arenot to be construed as being limited to the examples described herein.Rather, the examples described herein have been provided so that thisdisclosure will be thorough and complete, and will convey the full scopeof the disclosure to one of ordinary skill in the art.

In this application, a first lens refers to a lens closest to an object(or a subject), while a sixth lens refers to a lens closest to an imageplane (or an image sensor). Further, a first surface of each lens refersto a surface thereof closest to an object (or a subject), and a secondsurface of each lens refers to a surface thereof closest to an imageplane (or an image sensor). Further, all of radii of curvature,thicknesses, OALs (optical axis distances from a first surface of thefirst lens to the image plane), SLs (distances from a stop to the imageplane), IMGHs (image heights), and BFLs (back focus lengths) of thelenses, an overall focal length of an optical system, and a focal lengthof each lens are expressed in millimeters (mm). Further, thicknesses oflenses, gaps between the lenses, OALs, and SLs are distances measured inrelation to an optical axis of the lenses. Further, in a description forshapes of the lenses, a statement that one surface of a lens is convexmeans that an optical axis portion of a corresponding surface is convex,and a statement that one surface of a lens is concave means that anoptical axis portion of a corresponding surface is concave. Therefore,although it may be described that one surface of a lens is convex, anedge portion of the lens may be concave. Likewise, although it may bedescribed that one surface of a lens is concave, an edge portion of thelens may be convex.

A lens module includes an optical system including a plurality oflenses. As an example, the optical system of the lens module may includesix lenses having refractive power. However, the lens module is notlimited thereto. For example, the lens module may include othercomponents that do not have refractive power. As an example, the lensmodule may include a stop controlling an amount of light. As anotherexample, the lens module may further include an infrared cut-off filterfiltering infrared light. As another example, the lens module mayfurther include an image sensor (that is, an imaging device) convertingan image of a subject incident thereon through the optical system intoelectrical signals. As another example, the lens module may furtherinclude a gap maintaining member adjusting a gap between lenses.

First to sixth lenses may be formed of materials having a refractiveindex different from that of air. For example, the first to sixth lensesmay be formed of plastic or glass. At least one of the first to sixthlenses may have an aspherical surface shape. As an example, only thesixth lens of the first to sixth lenses may have an aspherical surfaceshape. As another example, at least one surface of all of the first tosixth lenses may be aspherical. Here, the aspherical surface of eachlens may be represented by the following Equation 1:

$\begin{matrix}{Z = {\frac{{cr}^{2}}{1 + \sqrt{1 - {\left( {1 + k} \right)c^{2}r^{2}}}} + {Ar}^{4} + {Br}^{6} + {Cr}^{8} + {Dr}^{10} + {Er}^{12} + {Fr}^{14} + {Gr}^{16} + {Hr}^{18} + {Jr}^{20}}} & (1)\end{matrix}$

Here, c is an inverse of a radius of curvature of a corresponding lens,k is a conic constant, and r is a distance from a certain point on anaspherical surface to an optical axis in a direction perpendicular tothe optical axis. In addition, constants A to J are respectively 4-thorder to 20-th order aspherical surface coefficients. In addition, Z isa distance between the certain point on the aspherical surface at thedistance r and a tangential plane meeting the apex of the asphericalsurface of the lens.

The lens module may have a wide field of view (FOV) of 74° or more.Therefore, the lens module may easily photograph a wide background orobject.

The optical system of the lens module satisfies the followingConditional Expression:

|r1/T1|<17.0.

Here, r1 is a radius of curvature in mm of an object-side surface of thefirst lens, and T1 is a thickness in mm of the first lens at an opticalaxis portion.

The above Conditional Expression is a condition for optimizingmanufacturing of the first lens. For example, in a case in which |r1/T1|is out of an upper limit value of the above Conditional Expression, itmay not be easy to make the first lens thin. In addition, in the case inwhich |r1/T1| is out of the upper limit value of the above ConditionalExpression, it may be difficult for the first lens to realize highresolution.

Meanwhile, the above Conditional Expression may also be optimized in thefollowing numerical range:

5.0<|r1/T1|<17.0.

The optical system of the lens module also satisfies the followingConditional Expression:

|f6/f|<79.0.

Here, f is an overall focal length in mm of the optical system includingthe first to sixth lenses, and f6 is a focal length in mm of the sixthlens.

The above Conditional Expression is a condition for optimizing anaberration correction effect by the sixth lens. For example, in a casein which |f6/f| is out of an upper limit value of the above ConditionalExpression, the sixth lens has excessively high refractive power, andthus it may not effectively correct aberration of the optical system.

Meanwhile, the above Conditional Expression may also be optimized in thefollowing numerical range:

3.0<|f6/f|<82.0.

The optical system of the lens module also satisfies the followingConditional Expression:

f5/f<−3.0.

Here, f is an overall focal length in mm of the optical system includingthe first to sixth lenses, and f5 is a focal length in mm of the fifthlens.

The above Conditional Expression is a condition for optimizing anaberration correction effect by the fifth lens. For example, in a casein which f5/f is out of an upper limit value of the above ConditionalExpression, the fifth lens may not effectively correct aberration.Conversely, in a case in which the above Conditional Expression issatisfied, the fifth lens has an excellent aberration correction effectand improves resolution of the lens module.

Meanwhile, the above Conditional Expression may also be optimized in thefollowing numerical range:

f5/f<−30.0.

The optical system of the lens module also satisfies the followingConditional Expression:

|(r7+r8)/(r7−r8)|<200.

Here, r7 is a radius of curvature in mm of an object-side surface of thefourth lens, and r8 is a radius of curvature in mm of an image-sidesurface of the fourth lens.

The above Conditional Expression is a condition for optimizing anaberration correction effect by the fourth lens. For example, in a casein which |(r7+r8)/(r7−r8)| is out of an upper limit value of the aboveConditional Expression, the fourth lens may not effectively correctaberration. Conversely, in a case in which the above ConditionalExpression is satisfied, the fourth lens has an excellent aberrationcorrection effect and improves resolution of the lens module.

Meanwhile, the above Conditional Expression may also be optimized in thefollowing numerical range:

2.0<|(r7+r8)/(r7−r8)|<200.

The optical system of the lens module also satisfies the followingConditional Expression:

|n3−n4|<0.10.

Here, n3 is a refractive index of the third lens, and n4 is a refractiveindex of the fourth lens.

The above Conditional Expression is a condition for optimizing materialsof the third and fourth lenses. For example, in a case in which |n3−n4|is out of an upper limit value of the above Conditional Expression, anaberration correction effect of the third and fourth lenses may beinsufficient. Conversely, in a case in which the above ConditionalExpression is satisfied, an aberration correction effect of the thirdand fourth lenses is excellent and a cost required for manufacturing thethird and fourth lenses is low.

The lens module may be manufactured in the following form.

As an example, the optical system of the lens module includes a firstlens having refractive power; a second lens having refractive power,both surfaces thereof being convex; a third lens having refractivepower, both surfaces thereof being concave; a fourth lens; a fifth lenshaving refractive power, an object-side surface thereof being convex;and a sixth lens having refractive power, an object-side surface thereofbeing convex.

As another example, the optical system of the lens module includes afirst lens having negative refractive power; a second lens havingpositive refractive power; a third lens having negative refractivepower; a fourth lens having negative refractive power; a fifth lenshaving negative refractive power; and a sixth lens having negativerefractive power.

Next, the main components of the lens module will be described.

The first lens may have refractive power. For example, the first lensmay have negative refractive power.

The first lens may have a meniscus shape. As an example, the first lensmay have a meniscus shape of which an object-side surface is convex or ameniscus shape of which an image-side surface is convex.

The first lens may have an aspherical surface. For example, bothsurfaces of the first lens may be aspherical. The first lens may beformed of a material having high light transmissivity and excellentworkability. For example, the first lens may be formed of plastic.However, a material of the first lens is not limited to plastic. Forexample, the first lens may be formed of glass.

The second lens may have refractive power. For example, the second lensmay have positive refractive power.

Both surfaces of the second lens may be convex. As an example, a firstsurface of the second lens may be convex and a second surface thereofmay be convex.

The second lens may have an aspherical surface. For example, bothsurfaces of the second lens may be aspherical. The second lens may beformed of a material having high light transmissivity and excellentworkability. For example, the second lens may be formed of plastic.However, a material of the second lens is not limited to plastic. Forexample, the second lens may be formed of glass. The second lens may beformed of a material having a high refractive index. For example, thesecond lens may be formed of a material having a refractive index of1.60 or more (in this case, the second lens may have an Abbe number of30 or less). The second lens formed of this material may easily refractlight even when having a small curvature shape. Therefore, the secondlens formed of this material may be easily manufactured and beadvantageous in lowering a defect rate depending on a manufacturingtolerance. In addition, the second lens formed of this material maydecrease a distance between lenses, and thus it may be advantageous inminiaturizing the lens module.

The third lens may have refractive power. For example, the third lensmay have negative refractive power.

Both surfaces of the third lens may be concave. As an example, a firstsurface of the third lens may be concave and a second surface thereofmay be concave.

The third lens may have an aspherical surface. For example, bothsurfaces of the third lens may be aspherical. The third lens may beformed of a material having high light transmissivity and excellentworkability. For example, the third lens may be formed of plastic.However, a material of the third lens is not limited to plastic. Forexample, the third lens may be formed of glass.

The fourth lens may have refractive power. For example, the fourth lensmay have negative refractive power.

The fourth lens may have a meniscus shape. For example, the fourth lensmay have a meniscus shape of which an object-side surface is convex or ameniscus shape of which an image-side surface is convex.

The fourth lens may have an aspherical surface. For example, bothsurfaces of the fourth lens may be aspherical. The fourth lens may beformed of a material having high light transmissivity and excellentworkability. For example, the fourth lens may be formed of plastic.However, a material of the fourth lens is not limited to plastic. Forexample, the fourth lens may be formed of glass.

The fifth lens may have refractive power. For example, the fifth lensmay have negative refractive power.

The fifth lens may be substantially convex toward the object side. As anexample, a first surface of the fifth lens may be convex and a secondsurface thereof may be concave.

The fifth lens may have one or more inflection points. As an example,the fifth lens may have one or more inflection points formed on a firstsurface thereof. As another example, the fifth lens may have one or moreinflection points formed on a second surface thereof. The fifth lensconfigured as described above may be convex toward the object side at anoptical axis portion and be concave at an edge portion.

The fifth lens may have an aspherical surface. For example, bothsurfaces of the fifth lens may be aspherical. The fifth lens may beformed of a material having high light transmissivity and excellentworkability. For example, the fifth lens may be formed of plastic.However, a material of the fifth lens is not limited to plastic. Forexample, the fifth lens may be formed of glass.

The fifth lens may be formed of a material having a high refractiveindex. For example, the fifth lens may be formed of a material having arefractive index of 1.60 or more (in this case, the fifth lens may havean Abbe number of 30 or less). The fifth lens formed of this materialmay easily refract light even when having a small curvature shape.Therefore, the fifth lens formed of this material may be easilymanufactured and be advantageous in lowering a defect rate depending ona manufacturing tolerance. In addition, the fifth lens formed of thismaterial may decrease a distance between lenses, and thus it may beadvantageous in miniaturizing the lens module.

The fifth lens may satisfy the following Conditional Expression. Thefifth lens satisfying the following Conditional Expression may be easilymanufactured.

5.0<|(r9+r10)/(r9−r10)|<21.0

Here, r9 is a radius of curvature of an object-side surface of the fifthlens, and r10 is a radius of curvature of an image-side surface of thefifth lens.

The sixth lens may have refractive power. For example, the sixth lensmay have positive or negative refractive power.

The sixth lens may have a meniscus shape of which an object-side surfaceis convex. As an example, a first surface of the sixth lens may beconvex, and a second surface thereof may be concave.

The sixth lens may include an inflection point. For example, the firstsurface of the sixth lens may be convex at the center of an opticalaxis, concave in the vicinity of the optical axis, and convex at an edgethereof. Likewise, the second surface of the sixth lens may be concaveat the center of an optical axis and become convex at an edge thereof.

The sixth lens may have an aspherical surface. For example, bothsurfaces of the sixth lens may be aspherical. The sixth lens may beformed of a material having high light transmissivity and highworkability. For example, the sixth lens may be formed of plastic.However, a material of the sixth lens is not limited to plastic. Forexample, the sixth lens may be formed of glass.

The image sensor may be configured to realize a high resolution of 1300megapixels. For example, a unit size of the pixels of the image sensormay be 1.12 μm or less.

The lens module may be configured to have a wide field of view. Forexample, the optical system of the lens module may have a field of viewof 74° or more. In addition, the lens module may have a relatively shortlength (OAL). For example, an overall length (distance from theobject-side surface of the first lens to the image plane) of the opticalsystem configuring the lens module may be 4.30 mm or less. Therefore,the lens module may be advantageously miniaturized.

FIG. 1 is a view of a first example of a lens module.

A lens module 100 includes an optical system including a first lens 110,a second lens 120, a third lens 130, a fourth lens 140, a fifth lens150, and a sixth lens 160. In addition, the lens module 100 furtherincludes an infrared cut-off filter 70 and an image sensor 80. Further,the lens module 100 may further include a stop (ST) (not shown). Forexample, the stop may be disposed between a subject (object) and thefirst lens 110.

In this example, the first lens 110 has negative refractive power, andan object-side surface thereof is convex and an image-side surfacethereof is concave. The second lens 120 has positive refractive power,and an object-side surface thereof is convex and an image-side surfacethereof is convex. The third lens 130 has negative refractive power, andan object-side surface thereof is concave and an image-side surfacethereof is concave. The fourth lens 140 has negative refractive power,and an object-side surface thereof is convex and an image-side surfacethereof is concave. The fifth lens 150 has negative refractive power,and an object-side surface thereof is convex and an image-side surfacethereof is concave. In addition, one or more inflection points areformed on each of the object-side surface and the image-side surface ofthe fifth lens. The sixth lens 160 has negative refractive power, and anobject-side surface thereof is convex and an image-side surface thereofis concave. In addition, one or more inflection points are formed oneach of the object-side surface and the image-side surface of the sixthlens.

In this example, all of the first lens 110, the third lens 130, thefourth lens 140, the fifth lens 150, and the sixth lens 160 havenegative refractive power as described above. Among these lenses, thefifth lens 150 has the strongest refractive power, and the third lens130 has the weakest refractive power.

FIG. 2 is a graph including curves representing MTF characteristics ofthe lens module illustrated in FIG. 1.

FIG. 3 is a graph including curves representing aberrationcharacteristics of the lens module illustrated in FIG. 1.

FIG. 4 is a table representing characteristics of the lenses of the lensmodule illustrated in FIG. 1. In FIG. 4, Surface Nos. 1 and 2 indicatethe first surface (object-side surface) and the second surface(image-side surface) of the first lens, and Surface Nos. 3 and 4indicate the first and second surfaces of the second lens. Similarly,Surface Nos. 5 to 12 indicate first and second surfaces of the third tosixth lenses, respectively. In addition, Surface Nos. 13 and 14 indicatefirst and second surfaces of the infrared cut-off filter.

FIG. 5 is a table representing aspherical surface coefficients of thelenses of lens module illustrated in FIG. 1. In FIG. 5, the labels ofthe columns are Surface Nos. of the first to sixth lenses, and thelabels of the rows are characteristics corresponding to each surface ofthe lenses.

FIG. 6 is a view of a second example of a lens module.

A lens module 200 includes an optical system including a first lens 210,a second lens 220, a third lens 230, a fourth lens 240, a fifth lens250, and a sixth lens 260. In addition, the lens module 200 furtherincludes an infrared cut-off filter 70 and an image sensor 80. Further,the lens module 200 may further include a stop (ST) (not shown). Forexample, the stop may be disposed between a subject (object) and thefirst lens.

In this example, the first lens 210 has negative refractive power, andan object-side surface thereof is concave and an image-side surfacethereof is convex. The second lens 220 has positive refractive power,and an object-side surface thereof is convex and an image-side surfacethereof is convex. The third lens 230 has negative refractive power, andan object-side surface thereof is concave and an image-side surfacethereof is concave. The fourth lens 240 has negative refractive power,and an object-side surface thereof is convex and an image-side surfacethereof is concave. The fifth lens 250 has negative refractive power,and an object-side surface thereof is convex and an image-side surfacethereof is concave. In addition, one or more inflection points areformed on each of the object-side surface and the image-side surface ofthe fifth lens. The sixth lens 260 has negative refractive power, and anobject-side surface thereof is convex and an image-side surface thereofis concave. In addition, one or more inflection points are formed oneach of the object-side surface and the image-side surface of the sixthlens.

In this example, all of the first lens 210, the third lens 230, thefourth lens 240, the fifth lens 250, and the sixth lens 260 havenegative refractive power as described above. Among these lenses, thefifth lens 250 has the strongest refractive power, and the third lens230 has the weakest refractive power.

FIG. 7 is a graph including curves representing MTF characteristics ofthe lens module illustrated in FIG. 6.

FIG. 8 is a graph including curves representing aberrationcharacteristics of the lens module illustrated in FIG. 6.

FIG. 9 is a table representing characteristics of the lenses of the lensmodule illustrated in FIG. 6. In FIG. 9, Surface Nos. 1 and 2 indicatethe first surface (object-side surface) and the second surface(image-side surface) of the first lens, and Surface Nos. 3 and 4indicate the first and second surfaces of the second lens. Similarly,Surface Nos. 5 to 12 indicate first and second surfaces of the third tosixth lenses, respectively. In addition, Surface Nos. 13 and 14 indicatefirst and second surfaces of the infrared cut-off filter.

FIG. 10 is a table representing aspherical surface coefficients of thelenses of the lens module illustrated in FIG. 6. In FIG. 10, the labelsof the columns are Surface Nos. of the first to sixth lenses, and thelabels of the rows are characteristics corresponding to each surface ofthe lenses.

FIG. 11 is a view of a third example of a lens module.

A lens module 300 includes an optical system including a first lens 310,a second lens 320, a third lens 330, a fourth lens 340, a fifth lens350, and a sixth lens 360. In addition, the lens module 300 furtherincludes an infrared cut-off filter 70 and an image sensor 80. Further,the lens module 300 may further include a stop (ST) (not shown). Forexample, the stop may be disposed between a subject (object) and thefirst lens.

In this example, the first lens 310 has negative refractive power, andan object-side surface thereof is concave and an image-side surfacethereof is convex. The second lens 320 has positive refractive power,and an object-side surface thereof is convex and an image-side surfacethereof is convex. The third lens 330 has negative refractive power, andan object-side surface thereof is concave and an image-side surfacethereof is concave. The fourth lens 340 has negative refractive power,and an object-side surface thereof is convex and an image-side surfacethereof is concave. The fifth lens 350 has negative refractive power,and an object-side surface thereof is convex and an image-side surfacethereof is concave. In addition, one or more inflection points areformed on each of the object-side surface and the image-side surface ofthe fifth lens. The sixth lens 360 has negative refractive power, and anobject-side surface thereof is convex and an image-side surface thereofis concave. In addition, one or more inflection points are formed oneach of the object-side surface and the image-side surface of the sixthlens.

In this example, all of the first lens 310, the third lens 330, thefourth lens 340, the fifth lens 350, and the sixth lens 360 havenegative refractive power as described above. Among these lenses, thefourth lens 340 has the strongest refractive power, and the third lens330 has the weakest refractive power.

FIG. 12 is a graph including curves representing MTF characteristics ofthe lens module illustrated in FIG. 11.

FIG. 13 is a graph including curves representing aberrationcharacteristics of the lens module illustrated in FIG. 11.

FIG. 14 is a table representing characteristics of the lenses of thelens module illustrated in FIG. 11. In FIG. 14, Surface Nos. 1 and 2indicate the first surface (object-side surface) and the second surface(image-side surface) of the first lens, and Surface Nos. 3 and 4indicate the first and second surfaces of the second lens. Similarly,Surface Nos. 5 to 12 indicate first and second surfaces of the third tosixth lenses, respectively. In addition, Surface Nos. 13 and 14 indicatefirst and second surfaces of the infrared cut-off filter.

FIG. 15 is a table representing aspherical surface coefficients of thelenses of the lens module illustrated in FIG. 11. In FIG. 15, the labelsof the columns are Surface Nos. of the first to sixth lenses, and thelabels of the rows are characteristics corresponding to each surface ofthe lenses.

FIG. 16 is a view of a fourth example of a lens module.

A lens module 400 includes an optical system including a first lens 410,a second lens 420, a third lens 430, a fourth lens 440, a fifth lens450, and a sixth lens 460. In addition, the lens module 400 furtherincludes an infrared cut-off filter 70 and an image sensor 80. Further,the lens module 400 may further include a stop (ST) (not shown). Forexample, the stop may be disposed between a subject (object) and thefirst lens.

In this example, the first lens 410 has negative refractive power, andan object-side surface thereof is concave and an image-side surfacethereof is convex. The second lens 420 has positive refractive power,and an object-side surface thereof is convex and an image-side surfacethereof is convex. The third lens 430 has negative refractive power, andan object-side surface thereof is concave and an image-side surfacethereof is concave. The fourth lens 440 has negative refractive power,and an object-side surface thereof is concave and an image-side surfacethereof is convex. The fifth lens 450 has negative refractive power, andan object-side surface thereof is convex and an image-side surfacethereof is concave. In addition, one or more inflection points areformed on each of the object-side surface and the image-side surface ofthe fifth lens. The sixth lens 460 has negative refractive power, and anobject-side surface thereof is convex and an image-side surface thereofis concave. In addition, one or more inflection points are formed oneach of the object-side surface and the image-side surface of the sixthlens.

In this example, all of the first lens 410, the third lens 430, thefourth lens 440, the fifth lens 450, and the sixth lens 460 havenegative refractive power as described above. Among these lenses, thefourth lens 440 has the strongest refractive power, and the third lens430 has the weakest refractive power.

FIG. 17 is a graph including curves representing MTF characteristics ofthe lens module illustrated in FIG. 16.

FIG. 18 is a graph including curves representing aberrationcharacteristics of the lens module illustrated in FIG. 16.

FIG. 19 is a table representing characteristics of the lenses of thelens module illustrated in FIG. 16. In FIG. 19, Surface Nos. 1 and 2indicate the first surface (object-side surface) and the second surface(image-side surface) of the first lens, and Surface Nos. 3 and 4indicate the first and second surfaces of the second lens. Similarly,Surface Nos. 5 to 12 indicate first and second surfaces of the third tosixth lenses, respectively. In addition, Surface Nos. 13 and 14 indicatefirst and second surfaces of the infrared cut-off filter.

FIG. 20 is a table representing aspherical surface coefficients of thelenses of the lens module illustrated in FIG. 16. In FIG. 20, the labelsof the columns are Surface Nos. of the first to sixth lenses, and thelabels of the rows are characteristics corresponding to each surface ofthe lenses.

FIG. 21 is a view of a fifth example of a lens module.

A lens module 500 includes an optical system including a first lens 510,a second lens 520, a third lens 530, a fourth lens 540, a fifth lens550, and a sixth lens 560. In addition, the lens module 500 furtherincludes an infrared cut-off filter 70 and an image sensor 80. Further,the lens module 500 may further include a stop (ST) (not shown). Forexample, the stop may be disposed between a subject (object) and thefirst lens.

In this example, the first lens 510 has negative refractive power, andan object-side surface thereof is concave and an image-side surfacethereof is convex. The second lens 520 has positive refractive power,and an object-side surface thereof is convex and an image-side surfacethereof is convex. The third lens 530 has negative refractive power, andan object-side surface thereof is concave and an image-side surfacethereof is concave. The fourth lens 540 has negative refractive power,and an object-side surface thereof is convex and an image-side surfacethereof is concave. The fifth lens 550 has negative refractive power,and an object-side surface thereof is convex and an image-side surfacethereof is concave. In addition, one or more inflection points areformed on each of the object-side surface and the image-side surface ofthe fifth lens. The sixth lens 560 has negative refractive power, and anobject-side surface thereof is convex and an image-side surface thereofis concave. In addition, one or more inflection points are formed oneach of the object-side surface and the image-side surface of the sixthlens.

In this example, all of the first lens 510, the third lens 530, thefourth lens 540, the fifth lens 550, and the sixth lens 560 havenegative refractive power as described above. Among these lenses, thefourth lens 540 has the strongest refractive power, and the third lens530 has the weakest refractive power.

FIG. 22 is a graph including curves representing MTF characteristics ofthe lens module illustrated in FIG. 21.

FIG. 23 is a graph including curves representing aberrationcharacteristics of the lens module illustrated in FIG. 21.

FIG. 24 is a table representing characteristics of the lenses of thelens module illustrated in FIG. 21. In FIG. 24, Surface Nos. 1 and 2indicate the first surface (object-side surface) and the second surface(image-side surface) of the first lens, and Surface Nos. 3 and 4indicate the first and second surfaces of the second lens. Similarly,Surface Nos. 5 to 12 indicate first and second surfaces of the third tosixth lenses, respectively. In addition, Surface Nos. 13 and 14 indicatefirst and second surfaces of the infrared cut-off filter.

FIG. 25 is a table representing aspherical surface coefficients of thelenses of lens module illustrated in FIG. 21. In FIG. 25, the labels ofthe columns are Surface Nos. of the first to sixth lenses, and thelabels of the rows are characteristics corresponding to each surface ofthe lenses.

The following Table 1 lists optical characteristics of the lens modulesof the first to fifth examples. The lens module has an overall focallength (f) of 2.70 to 2.80. A focal length (f1) of the first lens isdetermined in a range of −18.40 to −13.10. A focal length (f2) of thesecond lens is determined in a range of 1.80 to 1.90. A focal length(f3) of the third lens is determined in a range of −5.30 to −3.90. Afocal length (f4) of the fourth lens is determined in a range of −6140to −11.0. A focal length (f5) of the fifth lens is determined in a rangeof −1700 to −10.0. A focal length (f6) of the sixth lens is determinedin a range of −220 to −10.

TABLE 1 First Second Third Fourth Fifth Remarks Example Example ExampleExample Example f (EFL) 2.7370 2.7220 2.7330 2.7720 2.7590 f1 −18.418−13.230 −13.925 −16.185 −13.145 f2 1.8686 1.8723 1.8416 1.8591 1.8510 f3−5.0998 −5.2522 −4.2506 −4.0168 −5.0310 f4 −22.40 −11.89 −4706.89−6139.06 −100.03 f5 −99.82 −1698.86 −98.30 −270.54 −10.01 f6 −13.076−218.931 −17.014 −18.627 35.949 TTL 4.2290 4.3750 3.9570 3.9290 3.9790FOV 76.00 74.00 74.00 80.00 80.00

The following Table 2 lists values of Conditional Expressions of thelens modules of the first to fifth examples.

TABLE 2 Conditional First Second Third Fourth Fifth Expressions ExampleExample Example Example Example |r1/T1| 16.945 7.973 16.305 15.74713.165 |f6/f| 4.778 79.385 6.225 6.720 13.030 f5/f −36.472 −624.122−35.968 −97.599 −3.628 |(r7 + r8)/ 3.051 1.422 120.010 194.663 9.190 (r7− r8)| |n3 − n4| 0.000 0.000 0.070 0.070 0.000

As seen in Table 2, the lens modules of the first to fifth examplessatisfy all of the Conditional Expressions.

In the examples described above, the optical system has a highresolution.

While this disclosure includes specific examples, it will be apparent toone of ordinary skill in the art that various changes in form anddetails may be made in these examples without departing from the spiritand scope of the claims and their equivalents. The examples describedherein are to be considered in a descriptive sense only, and not forpurposes of limitation. Descriptions of features or aspects in eachexample are to be considered as being applicable to similar features oraspects in other examples. Suitable results may be achieved if thedescribed techniques are performed in a different order, and/or ifcomponents in a described system, architecture, device, or circuit arecombined in a different manner, and/or replaced or supplemented by othercomponents or their equivalents. Therefore, the scope of the disclosureis defined not by the detailed description, but by the claims and theirequivalents, and all variations within the scope of the claims and theirequivalents are to be construed as being included in the disclosure.

What is claimed is:
 1. A lens module comprising: a first lens having refractive power; a second lens having refractive power, both surfaces thereof being convex; a third lens having refractive power, both surfaces thereof being concave; a fourth lens having refractive power; a fifth lens having refractive power, an object-side surface thereof being convex; and a sixth lens having refractive power and having one or more inflection points on an image-side surface thereof, an object-side surface thereof being convex; wherein the first to sixth lenses are sequentially disposed in numerical order from the first lens to the sixth lens from an object side of the lens module toward an image side of the lens module.
 2. The lens module of claim 1, wherein an object-side surface of the first lens is convex.
 3. The lens module of claim 1, wherein an image-side surface of the first lens is convex.
 4. The lens module of claim 1, wherein an object-side surface of the fourth lens is convex.
 5. The lens module of claim 1, wherein an image-side surface of the fourth lens is concave.
 6. The lens module of claim 1, wherein an object-side surface of the fourth lens is concave.
 7. The lens module of claim 1, wherein an image-side surface of the fourth lens is convex.
 8. The lens module of claim 1, wherein an image-side surface of the fifth lens is concave.
 9. The lens module of claim 1, wherein the image-side surface of the sixth lens is concave.
 10. The lens module of claim 1, wherein |r1/T1|<17.0 is satisfied, where r1 is a radius of curvature of an object-side surface of the first lens, and T1 is a thickness of the first lens on an optical axis.
 11. The lens module of claim 1, wherein |f6/f|<79.0 is satisfied, where f is an overall focal length of an optical system comprising the first to sixth lenses, and f6 is a focal length of the sixth lens.
 12. The lens module of claim 1, wherein f5/f<−3.0 is satisfied, where f is an overall focal length of an optical system comprising the first to sixth lenses, and f5 is a focal length of the fifth lens.
 13. The lens module of claim 1, wherein |(r7+r8)/(r7−r8)|<200 is satisfied, where r7 is a radius of curvature of an object-side surface of the fourth lens, and r8 is a radius of curvature of an image-side surface of the fourth lens.
 14. The lens module of claim 1, wherein |n3−n4|<0.1 is satisfied, where n3 is a refractive index of the third lens, and n4 is a refractive index of the fourth lens.
 15. A lens module comprising: a first lens having negative refractive power; a second lens having positive refractive power; a third lens having negative refractive power; a fourth lens having negative refractive power; a fifth lens having negative refractive power; and a sixth lens having negative refractive power and having one or more inflection points on an image-side surface thereof; wherein the first to sixth lenses are sequentially disposed in numerical order from the first lens to the sixth lens from an object side of the lens module toward an image side of the lens module.
 16. The lens module of claim 15, wherein 5.0<|(r9+r10)/(r9−r10)|<21.0 is satisfied, where r9 is a radius of curvature of an object-side surface of the fifth lens, and r10 is a radius of curvature of an image-side surface of the fifth lens. 